Adam j



Patented Apr. ll, I899.

A. J. MAY.-

DENTAL CHAIR.

(Application filed Feb. 23, 1898.)

(No Model.)

5 1 E. 1 MQW ADAM J.

PATENT OFFICE.

MAY, OF ROCHESTER, NEW YORK, ASSIGNOR TO FRANK RITTER,

' OF SAME PLACE.

DENTAL- CHAIR.

SPECIFICATION forming part of Letters Patent No. 623,026, dated April 11, 1899.

Application filed February 23, 1898. Serial No. 671,272. (NomodeL) To all whom, it may concern:

Be it known that I, ADAM J. MAY, a resident of Rochester, in the county of Monroe and State of New York, have invented cer-' tain new and useful Improvements in Dental Chairs; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it pertains to make and use the same.

The invention relates to dental chairs, and has for its object to regulate the descent of the seat; and the invention consists in the construction hereinafter described and pointed out.

In the accompanying drawings, Figure 1 is a partial vertical section of the base and seatelevating and seatlowering tubes of a dental chair with the improvement applied thereto. Fig. 2 is a longitudinal section of the improved device on an enlarged scale.

Numeral 1 denotes a chair-base, and 2 a pedestal. 3 indicates a tube fixed in the base, and 4 a tube telescopically connected therewith and fixed to the cross-bar 5 of the chairseat frame, and 6 denotes a plunger. 7 denotes a pump for forcing liquid from the reservoir 8 into tube 3 and under the plunger 6 for the purpose of elevating the chair-seat. These parts may be of any usual or preferred construction.

To provide for lowering the seat, means are required for discharging at will from the tube 3 the liquid column which supports the seat in an elevated situation. 9 denotes a discharge tube or conduit for the purpose, and 10 a valve normally held to its seat 11 by a spring 12, thereby preventing outflow of liquid.

13 denotes the valve-stem, which preferably extends to the exterior of the chair-base and has its outer end situated under a lever 14, adapted to be depressed upon the valvestem to overcome the spring 12 and open the valve. This operation allows the liquid to escape from the tube 3 into the reservoir. It is practically important to vary the rate of this discharge, which necessarily varies with the combined weight of the chair-seat and its occupant, to avoid either too rapid or too slow descent of the seat, as the case maybe. In the particular form of the invention illustrated the discharge conduit-tube is pro-' longed beyond its valve-seat and made of a frusto-conical form and screw-threaded to receive the suitably-threaded tube 15, which surrounds the valve-stem.

16 indicates one or more ports formed in the conical part 9 of the tube 9 and within the end of tube 15, which latter is adapted to be screwed to and fro on said part 9', with the effect to partially close, more or less, the discharge-ports 16. In the case of a heavy sitter the discharging capacity of these ports can be restricted to avoid an undesirably-rapid descent of the seat and its occupant, and they can be uncovered more widely to avoid the contrary extreme inthe case of an occupant of small weight.

My improvement is not necessarily limited to the precise'arrangement and construction illustrated, but to devices having substantially the same principles of operation, it beingcharacteristic of the improvement that in dental chairs of the character herein indicated the rate of the discharge of the liquid seatsupporting column can be regulated at will and supplementary to or independent ofthe discharge-valve.

Having described my invention, what I claim is- 1. In a dental chair the combination of devices for raising and supporting a seat upon a liquid column, a tube for containing the said column, an exit-passage for the escape of liquid from said tube, a cock to open or close said passage at will, and adevice adapted to be set to provide exits of'dilferent capacity to vary, as predetermined, the rate of discharge of the liquid independently of regulation by the cock, substantially as described.

2. In a dental chair the combination of devices for raising and supporting a seat upon a liquid column, a tube for containing the said column, an exit-passage for the escape of liquid from said tube, a cock to open or close said passage at will, and a regulating device to vary the rate of discharge of the liquid independently of regulation by the cock, specification in the presence of two subscrilr said regulating device consisting of a screwing Witnesses. cap fitting a screw-threaded extension of the body of the cock and adapted to vary a dis- ADAM 5 charge-opening therein, substantially as de- Witnesses:

scribed. JNO. D. LYNN,

In testimony whereof I have signed this J OHN H. OHADSEY. 

